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EmscriptenPIC: Remove internalization of GOT entries #3211

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Merged
sbc100 merged 1 commit into from
Oct 13, 2020
Merged

EmscriptenPIC: Remove internalization of GOT entries #3211

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85 changes: 3 additions & 82 deletions src/passes/EmscriptenPIC.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -43,23 +43,6 @@

namespace wasm {

static Global* ensureGlobalImport(Module* module, Name name, Type type) {
// See if its already imported.
// FIXME: O(N)
ImportInfo info(*module);
if (auto* g = info.getImportedGlobal(ENV, name)) {
return g;
}
// Failing that create a new import.
auto import = new Global;
import->name = name;
import->module = ENV;
import->base = name;
import->type = type;
module->addGlobal(import);
return import;
}

static Function*
ensureFunctionImport(Module* module, Name name, Signature sig) {
// See if its already imported.
Expand Down Expand Up @@ -110,34 +93,8 @@ struct EmscriptenPIC : public WalkerPass<PostWalker<EmscriptenPIC>> {
Block* block = builder.makeBlock();
assignFunc->body = block;

bool hasSingleMemorySegment =
module->memory.exists && module->memory.segments.size() == 1;

for (Global* g : gotMemEntries) {
// If this global is defined in this module, we export its address
// relative to the relocatable memory. If we are in a main module, we can
// just use that location (since if other modules have this symbol too, we
// will "win" as we are loaded first). Otherwise, import a g$ getter. Note
// that this depends on memory having a single segment, so we know the
// offset, and that the export is a global.
auto base = g->base;
if (hasSingleMemorySegment && !sideModule) {
if (auto* ex = module->getExportOrNull(base)) {
if (ex->kind == ExternalKind::Global) {
// The base relative to which we are computed is the offset of the
// singleton segment.
auto* relativeBase = ExpressionManipulator::copy(
module->memory.segments[0].offset, *module);

auto* offset = builder.makeGlobalGet(
ex->value, module->getGlobal(ex->value)->type);
auto* add = builder.makeBinary(AddInt32, relativeBase, offset);
GlobalSet* globalSet = builder.makeGlobalSet(g->name, add);
block->list.push_back(globalSet);
continue;
}
}
}
Name getter(std::string("g$") + base.c_str());
ensureFunctionImport(module, getter, Signature(Type::none, Type::i32));
Expression* call = builder.makeCall(getter, {}, Type::i32);
Expand All @@ -147,52 +104,16 @@ struct EmscriptenPIC : public WalkerPass<PostWalker<EmscriptenPIC>> {

ImportInfo importInfo(*module);

// We may have to add things to the table.
Global* tableBase = nullptr;

for (Global* g : gotFuncEntries) {
// The function has to exist either as export or an import.
// Note that we don't search for the function by name since its internal
// name may be different.
auto* ex = module->getExportOrNull(g->base);
// If this is exported then it must be one of the functions implemented
// here, and if this is a main module, then we can simply place the
// function in the table: the loader will see it there and resolve all
// other uses to this one.
if (ex && !sideModule) {
assert(ex->kind == ExternalKind::Function);
auto* f = module->getFunction(ex->value);
if (f->imported()) {
Fatal() << "GOT.func entry is both imported and exported: "
<< g->base;
}
// The base relative to which we are computed is the offset of the
// singleton segment, which we must ensure exists
if (!tableBase) {
tableBase = ensureGlobalImport(module, TABLE_BASE, Type::i32);
}
if (!module->table.exists) {
module->table.exists = true;
}
if (module->table.segments.empty()) {
module->table.segments.resize(1);
module->table.segments[0].offset =
builder.makeGlobalGet(tableBase->name, Type::i32);
}
auto tableIndex =
TableUtils::getOrAppend(module->table, f->name, *module);
auto* c = LiteralUtils::makeFromInt32(tableIndex, Type::i32, *module);
auto* getBase = builder.makeGlobalGet(tableBase->name, Type::i32);
auto* add = builder.makeBinary(AddInt32, getBase, c);
auto* globalSet = builder.makeGlobalSet(g->name, add);
block->list.push_back(globalSet);
continue;
}
// This is imported or in a side module. Create an fp$ import to get the
// function table index from the dynamic loader.
// This is imported create an fp$ import to get the function table index
// from the dynamic loader.
auto* f = importInfo.getImportedFunction(ENV, g->base);
if (!f) {
if (!ex) {
if (!module->getExportOrNull(g->base)) {
Fatal() << "GOT.func entry with no import/export: " << g->base;
}
f = module->getFunction(ex->value);
Expand Down
20 changes: 0 additions & 20 deletions test/lld/gdollar_mainmodule.wat
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73 changes: 0 additions & 73 deletions test/lld/gdollar_mainmodule.wat.out
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21 changes: 6 additions & 15 deletions test/lld/main_module.wat.out
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Original file line number Diff line number Diff line change
Expand Up @@ -4,14 +4,14 @@
(type $i32_=>_i32 (func (param i32) (result i32)))
(import "env" "memory" (memory $0 0))
(data (global.get $gimport$2) "Hello, world\00\00\00\00\00\00\00\00\00\00\00\00")
(import "env" "table" (table $timport$1 1 funcref))
(elem (global.get $gimport$3) $print_message\28\29)
(import "env" "table" (table $timport$1 0 funcref))
(import "env" "__stack_pointer" (global $sp_import i32))
(import "env" "__memory_base" (global $gimport$2 i32))
(import "env" "__table_base" (global $gimport$3 i32))
(import "env" "puts" (func $puts (param i32) (result i32)))
(import "env" "g$external_var" (func $g$external_var (result i32)))
(import "env" "fp$puts$ii" (func $fp$puts$ii (result i32)))
(import "env" "fp$_Z13print_messagev$i" (func $fp$_Z13print_messagev$i (result i32)))
(global $gimport$5 (mut i32) (i32.const 0))
(global $gimport$6 (mut i32) (i32.const 0))
(global $gimport$7 (mut i32) (i32.const 0))
Expand All @@ -24,7 +24,6 @@
(export "ptr_puts" (global $global$0))
(export "ptr_local_func" (global $global$1))
(export "__data_end" (global $global))
(export "dynCall_i" (func $dynCall_i))
(export "__assign_got_enties" (func $__assign_got_enties))
(func $__wasm_call_ctors
(call $__wasm_apply_relocs)
Expand Down Expand Up @@ -66,31 +65,24 @@
(call $fp$puts$ii)
)
(global.set $gimport$7
(i32.add
(global.get $gimport$3)
(i32.const 0)
)
)
)
(func $dynCall_i (param $fptr i32) (result i32)
(call_indirect (type $none_=>_i32)
(local.get $fptr)
(call $fp$_Z13print_messagev$i)
)
)
)
(;
--BEGIN METADATA --
{
"staticBump": 4294966770,
"tableSize": 1,
"tableSize": 0,
"initializers": [
"__assign_got_enties",
"__wasm_call_ctors"
],
"declares": [
"puts",
"g$external_var",
"fp$puts$ii"
"fp$puts$ii",
"fp$_Z13print_messagev$i"
],
"externs": [
"___stack_pointer",
Expand All @@ -100,7 +92,6 @@
"exports": [
"__wasm_call_ctors",
"_Z13print_messagev",
"dynCall_i",
"__assign_got_enties"
],
"namedGlobals": {
Expand Down
24 changes: 6 additions & 18 deletions test/lld/main_module_table.wat.out
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Original file line number Diff line number Diff line change
@@ -1,51 +1,39 @@
(module
(type $none_=>_none (func))
(type $i32_=>_none (func (param i32)))
(type $none_=>_i32 (func (result i32)))
(import "env" "__stack_pointer" (global $sp_import i32))
(import "env" "__table_base" (global $__table_base i32))
(table $0 1 funcref)
(elem (global.get $__table_base) $__stdio_write)
(import "env" "fp$__stdio_write$v" (func $fp$__stdio_write$v (result i32)))
(global $gimport$9 (mut i32) (i32.const 0))
(global $global i32 (i32.const 42))
(global $sp (mut i32) (global.get $sp_import))
(export "__stdio_write" (func $__stdio_write))
(export "__data_end" (global $global))
(export "dynCall_v" (func $dynCall_v))
(export "__assign_got_enties" (func $__assign_got_enties))
(func $__stdio_write
(nop)
)
(func $__assign_got_enties
(global.set $gimport$9
(i32.add
(global.get $__table_base)
(i32.const 0)
)
)
)
(func $dynCall_v (param $fptr i32)
(call_indirect (type $none_=>_none)
(local.get $fptr)
(call $fp$__stdio_write$v)
)
)
)
(;
--BEGIN METADATA --
{
"staticBump": 4294966770,
"tableSize": 1,
"tableSize": 0,
"initializers": [
"__assign_got_enties"
],
"declares": [
"fp$__stdio_write$v"
],
"externs": [
"___stack_pointer",
"___table_base"
"___stack_pointer"
],
"exports": [
"__stdio_write",
"dynCall_v",
"__assign_got_enties"
],
"namedGlobals": {
Expand Down
25 changes: 7 additions & 18 deletions test/lld/main_module_table_2.wat.out
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Original file line number Diff line number Diff line change
@@ -1,51 +1,40 @@
(module
(type $none_=>_none (func))
(type $i32_=>_none (func (param i32)))
(import "env" "table" (table $timport$9 2 funcref))
(elem (global.get $__table_base) $__stdio_write)
(type $none_=>_i32 (func (result i32)))
(import "env" "table" (table $timport$9 1 funcref))
(import "env" "__stack_pointer" (global $sp_import i32))
(import "env" "__table_base" (global $__table_base i32))
(import "env" "fp$__stdio_write$v" (func $fp$__stdio_write$v (result i32)))
(global $gimport$9 (mut i32) (i32.const 0))
(global $global i32 (i32.const 42))
(global $sp (mut i32) (global.get $sp_import))
(export "__stdio_write" (func $__stdio_write))
(export "__data_end" (global $global))
(export "dynCall_v" (func $dynCall_v))
(export "__assign_got_enties" (func $__assign_got_enties))
(func $__stdio_write
(nop)
)
(func $__assign_got_enties
(global.set $gimport$9
(i32.add
(global.get $__table_base)
(i32.const 0)
)
)
)
(func $dynCall_v (param $fptr i32)
(call_indirect (type $none_=>_none)
(local.get $fptr)
(call $fp$__stdio_write$v)
)
)
)
(;
--BEGIN METADATA --
{
"staticBump": 4294966770,
"tableSize": 2,
"tableSize": 1,
"initializers": [
"__assign_got_enties"
],
"declares": [
"fp$__stdio_write$v"
],
"externs": [
"___stack_pointer",
"___table_base"
"___stack_pointer"
],
"exports": [
"__stdio_write",
"dynCall_v",
"__assign_got_enties"
],
"namedGlobals": {
Expand Down
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